1. Field of the Invention
The invention relates to an ink base for pigmented inks, inks made therefrom, as well as their use for printing, in particular, for use in ink-jet systems or other machine-based writing, printing, drawing or marking methods.
2. Description of the Related Art
Pigmented inks having a water-base and their use for inkjet printers are known in principle. Such inks according to the prior art are comprised of water, pigments as color-providing agents, drying retarders, and optionally other additives such as, for example, polymers, emulsifiers, preservatives, and surfactants. Drying retarders in inks according to the prior art, inter alia, are often, for example, glycols, glycerin, and pyrrolidones as well as mixtures of the these drying retarders.
In the following table, some examples of drying retarders used in such pigmented inks as well as their proportion in the ink in weight % (% by wt.) are listed.
InkDrying Retarderyellow ink 3.1% ethylene glycol 1.2% diethylene glycol 3.9% 2-pyrrolidone10.1% glycerine 6.8% butyl triglycolred ink (magenta)11.2% ethylene glycol 3.1% 2-pyrrolidone26.7% glycerine 6.7% butyl triglycolblue ink (cyan) 7.8% ethylene glycol 2.0% 2-pyrrolidone12.0% glycerine12.8% butyl triglycolblack ink 0.2% 1,2-propane diol 0.3% diethylene glycol 2.1% 2-pyrrolidone11.1% glycerine 4.3% triethylene glycol13.6% butyl diglycol
A disadvantage of such ink compositions is that such pigmented inks have a tendency to dry within the printing jets, to a substantially higher degree in comparison to, for example, the dye-based inks. Because of this, reliability cannot be ensured due to plugged and dried-up jets; this is manifested preliminarily already by an unsatisfactory printing quality. For this reason, it has been attempted to compensate this disadvantage by increasing the proportion of the drying retarder; however, this, in turn, also leads to disadvantages. In particular in the case of fast printers and when using inexpensive printing media in combination with inks having a high contents of drying retarders, this results in unsatisfactory contour sharpness and surface coverage. As a result of the increased drying time, the probability of smudging during printing and during removal from the printer is extremely high.
Moreover, the manufacturing costs of such inks according to the prior art are very high.